The invention relates to a seat belt retractor with hydraulic load limiting.
A known seat belt retractor comprises a belt reel for the seat belt and a blocking means for blocking rotation of a blockable part of the belt reel. The known seat belt retractor further comprises a load limiter, which consumes energy when the blocking means is activated and when the belt webbing carrier is rotated in the belt take-off direction relative to the blocked part of the belt reel. A load limiter is known from DE 199 63 580 C2 which comprises a cylinder filled with a viscous fluid, in which a piston is moved linearly with an opening comprising a variable flow cross-section as a flow path.
There is provided in accordance with the present invention A seat belt retractor comprising a frame with a belt reel having an axis of rotation rotatably mounted in the frame, a blocking means for blocking rotation of a blockable part of the belt reel, and a substantially drum-shaped belt webbing carrier on the belt reel, wherein in the belt webbing carrier there is arranged a rotor that is in rotary drive connection with the belt webbing carrier, the belt webbing carrier drives a toothed outer rotor and the rotor comprises a toothed inner rotor, wherein chambers filled a free-flowing medium are formed by intermeshing teeth of the outer rotor and the inner rotor and upon rotation of the rotor the volumes of at least two chambers filled with the free-flowing medium are varied, wherein the chambers rotate about the belt reel axis, and in the free-flowing medium flows in each case from a chamber diminishing in volume into a chamber increasing in volume.